Genes Matter

Autism Spectrum Disorder: What are the main characteristics?

Autism, or autism spectrum disorder (ASD), refers not only to a single disease but to a wide range of conditions. Autistic people may present challenges with social, communication and behavioural skills. Whilst ASD can be very different for each person, there are some common characteristics that we can identify at different stages in life. In this article, we’ll define ASD and review the common characteristics of this group of conditions.

What is autism?

We are used to identifying autistic people by the fact that they act differently from others starting at an early age, exhibiting a difficulty to communicate with their peers or perhaps finding it hard to understand how others feel. However, it is important to understand that autism is a much more complex manifestation of how the brain works.

Autism spectrum disorder refers to a complex neurodevelopmental disorder that impacts how a person perceives and relates to others, which can lead to problems in social interaction and communication.

It is important to note that each affected person shows specific signs with varying degrees of severity, therefore going through very different challenges and developing specific abilities. Consequently, the way in which people affected by ASD think, learn or solve problems can vary from relative ease to a severe challenge in some cases. Some people with ASD show above average intelligence, while others show learning difficulties.

In ASD genetic and non-genetic factors interact in the development of the condition. Characteristics of autism sometimes also includes sensory sensitivity and medical problems such as gastrointestinal disorders, sleep disorders, seizures, as well as mental health problems such as anxiety, depression, or attention difficulties. In 2013, the American Psychiatric Association published the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), in which condition as Asperger’s syndrome or pervasive developmental disorder not otherwise specified, are currently diagnosed under the umbrella of autism spectrum disorders.

Signs of autism in childhood

Despite the fact that each child with ASD is different from the others, and that the age of onset varies, it typically appears in the first 3 years of life. There are a series of warning signs that may make a comprehensive assessment of development recommendable. These are shown below, highlighting that the signs established in the previous stages can be present at any age. Of course, not all the children that presents any of these signs will be diagnosed with autism, the list below is just a guidance to have further specialized evaluation.

Between 12 and 18 months of age:

  • Doesn’t say simple words.
  • Doesn’t respond to his name.
  • Has limited or diminished use of eye contact.
  • Absence of social/communicative babble as if conversing with the adult.
  • Absence of spontaneous imitation.
  • Doesn’t point to “ask for something” (proto-imperative).
  • Doesn’t look where others point.
  • May manifest an unusual response to auditory stimuli.
  • Lack of interest in simple interactive games like “peek-a-boo” or the like.

Around 24 months of age:

  • Doesn’t say sentences of two or more words, which are spontaneous and not just repetitions of what he has heard from others.
  • Has difficulty maintaining eye contact when spoken to and does not follow objects with his eyes.
  • Doesn’t engage in shared games and does not seem to enjoy shared relationships with other people.

As they get older, children with ASD may develop some other tell-tale signs:

  • Doesn’t seem to understand how others think or feel, and find it difficult to express their own feelings.
  • Has speech delays or do not speak at all or lose the ability to say words or phrases that they had learned previously.
  • Become very attached to a daily routine and get angry if it changes.
  • Doesn’t understand expressions such as “it’s raining cats and dogs”, since they understand things literally.

What causes ASD: some factors involved in the onset of autism

At the moment, it is not possible to determine a single cause that explains the development of ASD, apart from the strong genetic implication in its origin. The estimated prevalence of ASD is about 1%-2%, being 2-3 times more frequent in males than in females.

Autism may result from disruption of normal brain foetal development early in stages, caused by defects in genes that control brain growth and regulate how neurons communicate with each other. Genetic causes including gene defects and chromosomal abnormalities have been found in 10-20% of affected individuals. In case of siblings born in families with ASD, they have a 50-times higher risk of ASD, with a recurrence rate of 5-8%.

In some cases, ASD can be associated with a genetic disorder already present, such as fragile X syndrome, meningitis infection, congenital rubella, phenylketonuria, or tuberous sclerosis.  

One crucial point to retain is that autism is not caused by childhood vaccines. There have been no correlations found in extensive studies around the occurrence of ASD and vaccinations.

Treatment of autism

Once a person who exhibits the characteristics of autism has been correctly diagnosed, there is no actual “cure” and treatment will vary depending on each personal case. There are various therapies that can be deployed early in a child’s life and they are more effective the sooner they are implemented.

The goal of ASD therapies is to maximize the ability of affected individuals to function, develop and learn.

Most people with ASD respond good to a highly structured and organized life. In some cases, these measures can help reduce symptoms and provide people with autism tools to accomplish their daily activities.

Diagnosing autism: how and when ASD is identified

Persons affected by autism usually exhibit symptoms as early as 2-3 years of age. For some cases, some developmental delays appear earlier and can be observed and diagnosed as early as 18 months of age.

However, because of the very personal and diverse nature of the symptoms ASD can entail, it can sometimes be difficult to diagnose the disorder and to determine its severity. Normally, a child’s doctor will check for signs of developmental delays as part of regular check-ups, and they will ask for a specialist to be consulted if any findings are detected.

When meeting with a specialist, there is unfortunately no specific medical test that can be done for an autism diagnosis. Instead, a specialist will try to observe the child and find out more about the nature of their social interactions, the level of their communication skills and how their behaviour have developed, as well as stablish the hearing, speech and language developmental levels.

Genetic testing can also be used to diagnose ASD. As we have mentioned above, genetic factors are associated with the development of autism. Several genes have been identified and are involved in the regulation of gene expression and in neuronal communication. Next Generation Sequencing (NGS) technology has shown to provide a higher diagnostic yield than other molecular approaches and, thanks to the technological advances together with the decrease in the sequencing costs, whole genome and exome sequencing are being positioning as first-tier tests in the genetic diagnosis of ASD.

Veritas offers genetic counselling for the patients and different diagnostic genetics options, including whole genome or exome sequencing with expert interpretation. Please contact us for more information about this service.

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1 comment

Lily Bridgers

29 August, 2023 3:55 pm

Thanks for talking about how even though every kid with ASD is unique and their start age varies, it usually manifests in the first three years of life. I will also remember that a thorough review of development may be advised due to a number of warning indicators. This will definitely be shared with my cousin whose son she suspects has this disorder. I hope they seek medical help for a proper autism diagnosis. Thanks.